One in five San Bernardino County homeowners are not making mortgage payments. That’s because they don’t have mortgages to pay off at all.

According to a research report by Zillow, 20 percent of San Bernardino County homeowners own their properties “free and clear” of debt.

That’s quite a bit lower than the national figure. Zillow estimates that 29 percent of U.S. homeowners own their homes outright. But don’t feel too bad about Ontario’s relatively low rate of free and clear homeownership. Washington, D.C.’s bedroom suburb of Leesburg, Va., has the lowest rate in the nation at 8 percent, according to Zillow.

The geographic differences in free-and-clear homeownership rates reflect both the differences in home values and demographics. Areas with more expensive homes tend to have fewer homes that are owned outright. Older homeowners, naturally, have had more time to pay off a 30-year mortgage.

But don’t write off young homeowners, either. Nationally, an estimated 35 percent of 20 to 24-year-old homeowners don’t have mortgages to pay off. Zillow researchers theorize that these very young homeowners either inherited their property or are in that lucky subclass of youthful millionaires.

Another intriguing finding involves credit scores. Those with the highest credit scores, with a Vantage score of 900 and above, have the lowest rate of free and clear ownership at just 16 percent. Zillow researchers suggest these homeowners are more likely to maintain a mortgage in order to diversify their financial holdings.

On the flip slide, those with the lowest credit scores, with Vantage scores under 600, have double that rate of debt-free homeownership. Some 29 percent of homeowners with the worst credit scores have no mortgage to worry about. That group tends to own less expensive homes and may have had to buy outright because they simply couldn’t qualify for a mortgage in the first place.